Relay cropping for improved air and water quality

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Excess soil nitrate contributes to water eutrophication and elevated nitrate in drinking water.
• Nitrous oxide (N2O) emissions from soil, a potent greenhouse gas, correlate with residual nitrate levels.
• Global climate change necessitates improved nitrogen (N) management in agriculture.

Purpose of the Study:

• To evaluate the efficacy of phytoremediation using winter wheat to scavenge soil nitrate.
• To assess the impact of incorporating winter wheat into a crop rotation on N2O emissions and water quality.
• To determine the economic benefits of this relay cropping system for producers.

Main Methods:

• Implementing a relay cropping sequence with winter wheat in a seed corn/soybean rotation.
• Measuring nitrate scavenging from the soil root zone.
• Quantifying crop residue production and producer profitability.

Main Results:

• The relay cropping sequence produced three crops in two years.
• Successfully scavenged 130 kg N/ha from the soil root zone.
• Generated an additional 2 Mg residue/ha and increased producer profitability by approximately $250/ha.

Conclusions:

• Phytoremediation with winter wheat is an effective strategy for nitrate management in agricultural systems.
• This approach mitigates environmental risks associated with excess soil nitrogen and contributes to climate change mitigation.
• Integrating winter wheat into existing rotations offers significant environmental and economic advantages.